This invention relates to a method for determining the storability or expected functional life of a grain or oilseed sample. The method can be practiced by grain storage operators, where the stored grain is exposed to fungus conditions that are not visible or readily discovered by cursory inspection of the grain.
Grain and oilseeds (e.g. corn, wheat, oats, soybeans, alfalfa or rice) are often stored for prolonged periods of time, in excess of one year, before being shipped to the end user. During the storage period, the grain is subject to fungus attack that can lead to grain spoilage. In the early stage of the fungus attack, the spoilage is not readily detectable by human inspection of the grain. The grain can appear to be in an acceptable condition.
It would be desirable to have a method for discovering incipient grain spoilage before the spoilage becomes evident and thus possibly beyond the point where corrective measures (such as grain drying) can be taken. The present invention relates to a method of detecting the onset of grain spoilage before the spoilage condition is self evident.
The method of this invention utilizes the fact that fungal growth in grain is accompanied by the generation of gaseous carbon dioxide. By measuring the rate at which carbon dioxide is produced in a grain sample it is possible to form some useful conclusions as to the progress of the fungus attack and expected functional life of the grain. The term xe2x80x9cfunctional lifexe2x80x9d is here used to mean the time that the grain can remain in storage before the grain experiences unacceptable deterioration.
The present invention uses a carbon dioxide detection system that is similar to a system disclosed in U.S. Pat. No. 5,320,807, issued to W. Brinton and M. Droffner on Jun. 14, 1994. The system of U.S. Pat. No. 5,320,807 is here modified to the extent that carbon dioxide measurements in the atmosphere proximate to the sample are taken periodically to establish a plot of carbon dioxide concentration versus time. The calculated rate of carbon dioxide generation can be used to form conclusions as to the expected functional life of the grain being sampled.
In preferred practice of the invention, the carbon dioxide measurements are supplemented by measurement of the moisture content of the grain being sampled The grain moisture content is an important influence on the rate of grain deterioration. A higher moisture content will generally accelerate fungus growth, so that higher moisture readings in conjunction with high carbon dioxide generation provide an important signal to the person charged with protecting the grain against fungus attack. For example, high CO2 production at low moisture content indicates a more deteriorated (i.e. more fungal growth) condition than that same CO2 production rate at high moister content.
Features and advantages of the invention will be apparent from the attached drawings and description of an illustrative method of practicing the invention.